There is known a direct injection gasoline as well as Diesel engine in which each of the fuel injectors is disposed in the substantial center of four intake and exhaust ports of the cylinder head.
In this direct injection engine, each of the fuel injectors is inserted into each attachment hole formed in the cylinder head.
The fuel injector inserted in the cylinder head in this way is then fixed to the cylinder head by an injector push arm arranged at the top of the cylinder head (see Japanese Unexamined Utility Model Publication (kokai) No. 6-69360 and 60-57775, Japanese Unexamined Patent Publication (kokai) No. 4-76208, the same 6-221248, and Japanese Unexamined Utility Model Publication (kokai) No. 4-43242).
One example of conventional devices, as disclosed in the Japanese Unexamined Utility Model Publication No. 60-57775, for fixing the fuel injectors to the cylinder head by the injector push arms will be explained hereinafter. The injector push arm is provided, at a leading end thereof, with a pusher part which comes into contact with an end of the fuel injector opposite to a fuel injection nozzle. At the rear end of the injector push arm, a support part is formed so as to abut on a head part of a cylinder head bolt. Between the pusher part and the support part of the injector push arm, an attachment part is provided with a through hole through which a stud bolt is screwed into a cylinder head.
Owing to the provision of the pusher part abutting on the fuel injector, the support part abutting on the head part of the cylinder head bolt and the attachment part fixed to the cylinder head through the stud bolt, the injector push arm serves to fix the fuel injector to the cylinder head. In this fixing arrangement, a contact between the head part of the cylinder head bolt and the support part constitutes a fulcrum of the injector push arm.
The inventor of the present invention has recognized disadvantages with the prior art arrangements, especially when these are applied to an over-head camshaft (OHC) engine.